Nitric oxide is responsible for activating new precursor cells for skeletal muscle growth and muscle repair from injury or disease. Sufficient blood flow to muscles and other organs that are recruited during any types of physical exercise is often necessary to meet an increased demand in nutrients by these muscles and organs. The endothelium of blood vessels uses nitric oxide to signal the surrounding smooth muscle to relax, thus resulting in vasodilation and increasing blood flow. NO production is important for increasing vasodilation to meet the increased demand in nutrients by muscles and organs during physical exercise. Due to the role that nitric oxide plays in muscle growth and repair, it is also important in various muscular and neuromuscular diseases.